A Review of Kuehneotherium & its Mammaliaforme Relatives From Upper Triassic France

The origin and first diversification of mammals in the Upper Triassic remain poorly understood, in part because many fossil discoveries are not fully studied, and in part because the material remains poor. The Saint-Nicolas-de-Port quarry (Rhaetian, France) is the second most important locality that yielded remains of Kuehneotherium, after the fissure-fillings of the Glamorganshire (Lower Jurassic, Wales). This study identifies one new species of Kuehneotherium, K. stanislavi, sp. nov., and a new genus of Kuehneotheriidae, Fluctuodon necmergor, gen. et sp. nov. For these two new species, lower and upper molars are described and the first reconstructions of the postcanine row are proposed. Comparisons with material of Kuehneotherium from other Upper Triassic sites (Syren in Luxembourg, Emborough in England, and Jameson Land in Greenland) suggest two distinct Upper Triassic specific kuehneotheriid assemblages, respectively, west and east of the London Brabant Massif. They also suggest that the extinction event during the Triassic/Jurassic transition did not have a great impact on Kuehneotherium.